A Weight-Bind-Based Safe Top-k Query Processing Scheme in Two-Tiered Sensor Networks

Privacy and integrity are two important requirements in cyber security. Because of the limited computing capability and resources of sensor nodes, it is a great challenge to meet these two requirements at the same time for top-k queries in two-tiered sensor networks. In this paper, a weight-bind-based safe top-k query processing scheme named WBB-TQ (Weight-Bind-Based safe top-k Query processing scheme) is proposed to solve this problem. WBB-TQ combines the pair-wise-key encryption technique and the order-preserving symmetric encryption scheme (OPES) so that the storage nodes at the upper layer of the network can process top-k queries without knowing the exact values of either sensing data or their corresponding scores. Thus, the data privacy for top-k queries is preserved. To achieve the integrity of top-k query results, a novel weight-bind-based method is proposed in WBB-TQ to establish relationships among data items generated by each sensor node so that the Sink node can detect whether adversaries drop and/or tamper with part or all of the qualified top-k data items in the query results. Simulation results show that, WBB-TQ not only preserves data privacy and integrity of top-k query results, but also achieves a low cost of computation and communication on secure top-k query processing in two-tiered sensor networks.